Bedrock Geology of the Eastern Gila Bend Mountains, Maricopa County, Arizona, scale 1:24,000.

The eastern Gila Bend Mountains, Maricopa County, Arizona, are composed of Early Proterozoic crystalline rocks and overlying mid-Tertiary continental clastic and volcanic rocks of the Sil Murk Formation. Slightly more than half of the bedrock in the eastern Gila Bend Mountains is composed of granitic rocks, mainly located in the eastern and northern part of the map area. Except for a few scattered exposures, the Tertiary continental clastic and volcanic rocks crop out in the southwest part of the map area. The eastern Gila Bend Mountains were mapped with funds provided to the Arizona Geological Survey by the U.S. Geological Survey COGEOMAP program, contract #14-08-001-A0785. Field work was carried out from December, 1990 to February, 1991. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.